Final thread needed to crack enduring cold case

DETECTIVES believe they know who killed Marilyn Wallman, and all they need is for a member of the public to come forward with the final shred of evidence.

In an extraordinary move never before seen in Queensland, police have doubled the reward for information that will bring the schoolgirl's killer to justice after more than 46 years.

Marilyn Joy Wallman was 14 years old when she vanished near Wallmans Rd and Eimeo Rd while riding her bicycle to the school bus stop on March 21, 1972. Her brothers Rex and David, who had followed her on the same route some time after, found her bicycle and school bag.

A skull fragment was found in 1974, about 40km from where she went missing, and modern DNA testing in 2015 concluded it was Marilyn's.

Police Minister Mark Ryan yesterday approved increasing the reward from $250,000 to $500,000, for a temporary period of 12 months, honouring a request made to him personally by the Wallman family.

"There was the opportunity for the [Police] Commissioner and I to meet with Mr Wallman a few months ago in Mackay," he said.

"We listened to his story and we listened to his advocacy around what he thought was needed to provide that incentive to the community to help crack this case."

Sarina CIB Detective Senior Constable Cindy Searle, the lead investigator on the cold case for the past three years, yesterday said the person of interest police believe could help solve the crime still resided within the Mackay Police District.

This person of interest has been on police books since a review of the cold case about four years ago. It is understood there are about a dozen boxes of police files pertaining to Marilyn's murder.

"We feel like we are very very close to an answer. Unfortunately, we just need a little bit more public assistance with that," she said.

"If we can get some information from the public who have knowledge, I believe that we could [get an arrest].

"I believe somebody somewhere knows something."

Det Snr Constable Searle also revealed no further investigations would be carried out at the site where the skull fragment was found.

Scientists and excavators searched the site on Mirani- Mt Ossa Rd in March 2016. She said the decision was made not to investigate the site further after "significant information" from scientists involved in soil testing.

The two-tone aqua and white Holden sedan, believed to be a HD or HR model, which was seen around Wallmans Rd at the time of Marilyn's disappearance remains a vital clue in the investigation.

"We are starting to run out of time with witnesses being still alive to speak to," Det Snr Constable Searle said.

"We are doing everything we can to try and resolve the matter and identify the person, formally, who is responsible for the murder of Marilyn."

The Wallman family declined to comment yesterday. Marilyn's brother Rex said a family meeting was being held yesterday to decide the way forward.

"Our message is, please come forward, the family has lived for 46 years not knowing what has happened to their daughter," Det Snr Constable Searle said. "We would like to be able to give them answers."

March 21, 1972: Marilyn Wallman, 14, left home on a bicycle and began her ride to the Rural Youth Hall to catch an 8am school bus. Her brothers David and Rex find her bag and bicycle on the side of the road.

October 1974: Railway worker Greven Breadsell finds part of a skull near Mirani, about 40km from where Marilyn went missing.

February 2014: Police begin an excavation of a backyard in Bassett St, North Mackay. After several days nothing was found.

March 6, 2015: Marilyn Wallman was farewelled amid a sea of yellow flowers by friends and family wearing her favourite colour, yellow, on what would have been her 57th birthday.

March 15, 2016: Detectives confirm scientific officers took soil samples from a property on Mirani-Mt Ossa Rd, near McGregor Ck.

September 11, 2018: Queensland Police temporarily double reward for information to $500,000, as the window to capture Marilyn's killer closes 46 years on. Detectives reveal the person of interest still resides within the Mackay Police District.